1691420640 has 192 divisors, whose sum is σ = 6557677056. Its totient is φ = 356861952.

The previous prime is 1691420623. The next prime is 1691420651. The reversal of 1691420640 is 460241961.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24319 + ... + 63041.

It is an arithmetic number, because the mean of its divisors is an integer number (34154568).

Almost surely, 2^1691420640 is an apocalyptic number.

1691420640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1691420640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3278838528).

1691420640 is an abundant number, since it is smaller than the sum of its proper divisors (4866256416).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1691420640 is a wasteful number, since it uses less digits than its factorization.

1691420640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38761 (or 38753 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 1691420640 is about 41126.8846376674. The cubic root of 1691420640 is about 1191.4720948131.

The spelling of 1691420640 in words is "one billion, six hundred ninety-one million, four hundred twenty thousand, six hundred forty".